The invention relates to a door-locking device for a household appliance, comprising a base member with a receptacle into which a closing element on the door side can move when the door of the household appliance is closed, an electric switch that can switch to a closed position of the closing element and that can transmit to a control unit an information signal indicating the closed position of the closing element and comprising an interlocking device for mechanically interlocking the door, wherein the mechanical interlocking is possible in an interlock position of the closing element. The invention further relates to a door arrangement comprising such a door locking device. The invention finally relates to a method for locking a door of a household appliance using such a door locking device.
With such a door locking device for a household appliance for laundry care, after the door (also referred to as the window) has been closed, an electrical switch is closed which has the task of signaling to a control unit of the household appliance that a closed position of the door has been reached. In this closed position the mechanical interlocking of the door must have already been made possible by an interlocking device so that the electrical switch remains closed for a door that is already interlocked. In this case the closed position, in which the electrical switch is closed can for constructional reasons not be provided at the same place as the interlock position in which the mechanical interlocking of the door is made possible. For these reasons first the closed position and then the interlock position is assumed when the door is closed. The result achieved by this is that, when an attempt is made to open the door by a user in an interlocked state of the door, the electrical switch is not inadvertently opened.
As from September 2006 BSH Bosch und Siemens Hausgeräte GmbH has been marketing washing machines under the brand names Bosch and Siemens each of which features a door locking device of the generic type described above.
Door locking devices can also be found in the two documents WO 2006/122842 A1 and WO 2007/065793 A1.
One of the current BSH Bosch und Siemens Hausgeräte GmbH door locking devices 1 for a household laundry care appliance is shown in schematic diagrams in FIGS. 1 to 6. These diagrams show the different positions of a door-side closing element 2, which on closure of a door of the household appliance, is able to be moved into a corresponding receptacle 3 of a base member 4. The base member 4 can for example be a part of a housing of the household appliance. This door locking device 1 features a sliding element 5 which is able to be moved in relation to the base member 4. The sliding element 5 has a receptacle opening 6 to accept the closing element 2 which directly adjoins the receptacle 3 of the base member 4. It should be mentioned at this point that the closing element 2 is supported pivotably on the door of the household appliance and has a positioning force applied to it, for example is spring-loaded. This means that the closing element 2 can be hinged from a basic position shown in FIG. 1 into a hinged position shown in FIG. 2, with the positioning force making sure that the closing element 2 is able to be moved automatically from the hinged position into the basic position. With this door locking device 1 the sliding element 5 is able to be moved when the closing element 2 is moved into the receptacle opening 6 by an exertion of a force effected by the closing element 2 on a side wall of the receptacle opening 6. This force is attributable to the positioning force that is applied to the closing element 2.
This door locking device 1 further features an electrical switch 8 which is formed by a contact element pair including a first and a second contact element 9, 10. The first and the second contact element 9, 10 are held in this case on the base member 4 and/or on the housing of the household appliance and are also embodied to be flexible or elastic and springy respectively. With this door locking device 1 the electrical switch 8 is able to be switched by means of the sliding element 5 into its closed switching position. For this purpose the sliding element 5 has a flange-type protrusion 11 projecting from it by means of which the first contact element 9 is bent and can thus be moved towards the second contact element 10 in order to establish an electrical connection between the first and the second contact element 9, 10. If the closing element 2 effects a movement of the sliding element 5, the electrical switch 8 can be closed. In this case the switching of the electrical switch 8 into its closed switching state occurs in a closed position of the closing element 2 in the receptacle 3, i.e. accordingly in a closed position of the sliding element 5 in relation to the base member 4. The fact that the closed position of the closing element 2 has been achieved is signaled to a control unit of the household appliance via the electrical switch 8.
This door locking device 1 further comprises an interlocking device 12 having an interlocking element 13 which is able to the inserted into a corresponding opening 14 of the sliding element 5. In this case the interlocking element 13 can only be inserted into the corresponding opening 14 of the sliding element 5 if an interlock position of the closing element 2 shown in FIG. 4 and correspondingly an interlock position of the sliding element 5 in relation to the interlocking element 13 is passed. Furthermore an electrical interlocking switch 15 is assigned to the interlocking device 12 which is formed by a contact element pair including a first and a second contact element 16, 17. In this case the first and the second contact element 16, 17 of the interlocking switch 15 are held on the base member 4 and/or on the housing of the household appliance and are embodied flexibly or elastically and springy respectively. In addition the first contact element 16 is pre-tensioned by means of the interlocking element 13 and in more precise terms by means of a flange-type lug 18 protruding from said element, so that on insertion of the interlocking element 13 into the opening 14 of the sliding element 5 the first contact element 16 is automatically caused to move towards the second contact element 17 to make an electrical connection between the first and the second contact element 16, 17. The electrical interlocking switch 15 in this case has the task of signaling to a control unit of the household appliance the locked state of the door.
A closing process of the door of the household appliance is explained below in greater detail with reference to FIGS. 1 to 6. In a position of the closing element 2 depicted in FIG. 1 the electrical switch 8 as well as the electrical interlocking switch 15 is opened and the mechanical locking of the door is not possible because of the displaced position of the opening 14 in relation to the interlocking element 13. This position of the closing element 2 corresponds to an open position of the door of the household appliance. When the door is closed the closing element is moved into the receptacle 3 of the base member 4 as well as into the receptacle opening 6 of the sliding element 5 and thus, as a result of the positioning force, causes the sliding element 5 to move in relation to the base member 4. A closed position of the closing element 2 is shown in FIG. 2, in which the electrical switch 8 is switched into its closed or electrically-conductive switching state. The time of actuation of the electrical switch 8 or of reaching the closed position of the closing element 2 is not fixed in this case but depends on the mechanical tolerances, especially on construction and manufacturing-related variations in shape and position of the electrical switch 8 and of the flange-type projection 11. Referring to FIG. 7, a first Gaussian curve 19 represents a probability density of the probability of reaching the closing position of the closing element 2 or the closing of the electrical switch 8 as a function of the current position S of the closing element 2 on closing the door of the household appliance. As FIG. 7 shows, when a first position 51 of the closing element 2 is passed, the closed position of said element is very probably reached, i.e. it is highly likely that the electrical switch 8 is closed. In this case the shape, especially the width of the first Gaussian curve 19, is determined by the mechanical tolerances.
Again referring to FIG. 2, in the closed position of the closing element 2 the mechanical interlocking of the door of the household appliance is not yet possible because of the displaced position of the opening 14 in relation to the interlocking element 13. A further position of the closing element 2 after the closed position of the same is shown in FIG. 3. Although in this position of the closing element 2 in accordance with FIG. 3 the mechanical interlocking the door is not yet guaranteed, this is however likewise dependent on the build tolerances, such as especially on the shape and position tolerances of the sliding element 5 and of the interlocking element 13. Shown in FIG. 7 by a second Gaussian curve 20 is a probability density of the probability of reaching the interlock position of the closing element 2 as a function of the current position S of the same. As is shown in FIG. 7, the interlock position of the closing element 2, in which the mechanical interlocking of the door is made possible, is very probably reached at a position S2 of the closing element 2. This position S2 corresponds to the position of the closing element 2 which is reproduced in FIG. 4. On reaching the interlock position of the closing element 2 shown in FIG. 4, both the electrical switch 8 is closed and also the mechanical interlocking of the door is made possible. A further position of the closing element 2 which corresponds to an end position of the same, is shown in FIGS. 5 and 6. As can be seen from these figures, the interlocking element 13 can be guided into the opening 14 and can be withdrawn from said opening. In this end position the mechanical interlocking the door is assured, i.e. is possible with a probability equal to almost one, which is shown with reference to an interlocking curve 21 in FIG. 7. In this case the interlocking curve 21 can assume two different values, a value V1 and also a value V2. If the interlocking curve 21 assumes the value V2, the mechanical interlocking of the door of the household appliance is made possible. By contrast the value V1 means that the probability of reaching the interlock position of the closing element 2 is less than 1. Further referring to FIG. 7, a switching curve 22 represents possible switching states of the electrical switch 8. In this case a value X1 corresponds to the open switching state and a value X2 to the closed switching state of the electrical switch 8. As is shown in FIG. 7, one hundred percent information about the closed switching state of the electrical switch 8 can only be provided at the end of the first Gaussian curve 19, i.e. when the closed position of the closing element 2 is reached with the probability equal to almost one. The end position of the closing element 2 in which the electrical switch 8 is closed and the mechanical interlocking of the door is made possible is labeled S3 in FIG. 7.
As stated above, with this door locking device 1, first the closing position in which the electrical switch 8 is closed and then the interlock position, in which the mechanical interlocking of the door is made possible, is achieved. The situation which is to be seen as a disadvantage for this door locking device 1 is the situation in which for a closed electrical switch 8 via which the closed position of the closing element 2 is able to be signaled to the control unit, the mechanical interlocking of the door is not always made possible. Because of the build tolerances mentioned, there are states in which the closed position is signaled to the control unit via the closed electrical switch 8 but the mechanical interlocking of the door and thus the closing of the electrical interlocking switch 15 is not possible however, so that a process of the household appliance, such as a wash cycle for example, cannot be started.
The underlying object of the present invention is to create a door locking device for a household appliance, a door arrangement with such a door locking device and also a method for locking a door of a household appliance, wherein measures are taken which guarantee that the mechanical interlocking of the door is able to the carried out in an operationally-secure manner when the electrical switch is closed.